Problem: Simplify the expression. $(-3k^{4}-2k^{2}+5k)(-7k^{2}-5k)$
Answer: First use the distributive property. $ - 3 k^4 (-7 k^2) - 3 k^4 (-5 k) - 2 k^2 (-7 k^2) - 2 k^2 (-5 k) + 5 k (-7 k^2) + 5 k (-5 k) $ Simplify. $ 21k^{6} + 15k^{5} + 14k^{4} + 10k^{3} - 35k^{3} - 25k^{2} $ $21k^{6}+15k^{5}+14k^{4}-25k^{3}-25k^{2}$ Identify like terms. $ { 21k^{6}} {+ 15k^{5}} {+ 14k^{4}} {+ 10k^{3}} {- 35k^{3}} {- 25k^{2}} $ Add the coefficients. $ { 21k^{6}} {+ 15k^{5}} {+ 14k^{4}} { -25k^{3}} { -25k^{2}} $